trying to avoid being duped on a consumer unit

There are two kinds of consumer unit layouts which sparks install to current regulations, one is a split load unit and the other is a high integrity fully populated RCBO consumer unit both are metal clad(no plastic housings).

Split load is the most common as it is cheaper and meets the basic requirements for a minimum of two RCD protected banks for your domestic circuits. These are usually in a house split so you have all downstairs circuits on one RCD protected bank and all upstairs circuits on the other protected bank. This allows for faults that occur either upstairs or downstairs to only disconnect either or bank and not the entire house from power.
If you choose a fully populated RCBO setup then each circuit has a dedicated protection so if a fault occurs on a socket it will only disconnect that ring final and nothing else. It is the most premium(if we can call it that) setup.

Yes they need RCD protection, there are very few cases that a domestic installation won't need RCD protection.

It is always best to have your garage supply separate from the house consumer unit and you can ask the electrician to split the tails so you have a separate isolation/consumer unit for your garage. Talk to your electrician on this... He will need to discover what type of installation you currently have supplied by the energy supplier such as PME etc.

Lights are usually 1-1.5mm2 cable 6Amp
Ring finals are 2.5mm2 cable 32Amp
Radials are usually 2.5-4mm2 16, 20 - 32Amp
Cookers are usually 6mm2 cable 32Amp but can be 40Amp depending on cable used such as larger 10mm2.
Immersion heaters are usually 6-10mm2 cable 32 -40 again depending on power requirement and cable used.

Current ratings for each circuit are defined by cable size and circuit type so if you pull 2.5mm2 for your sockets in a radial then you can't have it on a 32Amp. It must be 4mm2 radial or a 2.5mm2 ring final to use a 32Amp RCBO/MCB.

As for your conservatory well that depends on what electrics are in the conservatory such as socket or just a light. If you use RCBO's you can have a dedicated conservatory light circuit and a dedicated radial circuit for sockets again all RCD protected and yes you can do this with a split load unit too, only if a fault occurs with your conservatory circuits that disconnects that RCD bank it will take down your downstairs circuits with it.

Qualifications...
They need to be registered electricians with Part P registration as well and they will have a plastic ID card showing this. Consumer Units are building control notifiable job so they MUST be Part P registered. If not you will end up with some serious charges from Building Control to get it signed off.

That is the bulk of it in a nutshell so hope it helps

 

Technically you need too call up your power company and have them install a double pole isolation switch in the tails just after the meter, that way they cut and re-seal the cutout.
Contact your energy supplier to see what it would cost, maybe ask them for two isolations one for your house consumer and the other for the garage and see what they say.

 

Get a pukka sparks in to quote for the whole job - if you dont like the quote then no need to go ahead.

Not sure that I agree with the two isolators Fire

 

Reckon sparky would install his isolator I know I do as said above get registered sparks in to quote for whole job it be easier in long run, always say going cheap not always best

 

When you find a spark, ask what certification body they are with. Then you can visit the relevant website to check they are registered.

 

One isolator, then henleys!!!

 

Most sparks wouldn't sign of wiring that they haven't installed!!!!!!

 

Whoever quotes you, look at the quotes to make sure your getting a like for like quote, can't even count the amount of times I have been out priced by the cowboys, insist on a Part P notification and an installation certificate and only use a registered spark, you will find plenty of idiots installing boards and leaving no paperwork. to find one near you enter your post code into this web site and all registered sparks will be listed. http://www.electricalcompetentperson.co.uk/

 

No spark should sign off wiring they have not installed but we live in a capitalistic environment that allows corporations to employ qualified sparks under their registration.

I quit being self employed in spark trade years ago because i did not agree with where the industry was heading, now i demand a PAYE check at the end of the week. Soon the days of the local self employed tradesmen will be a thing of the past the way things are going, it just don't pay any more.
The benefits of being a sole trader is just not as good anymore compared to the greater safety and security of working for a large firm.

The ability to sign off someone else work is available only for DIY and firms who have several sparks employed on the books(contract).

A DIYer has to contact their local building control and notify them of the work they wish to do, as they do the work a building control inspector must come out and inspect the cable chasing etc, after it is installed a registered spark needs to test the circuit and produce a test cert for the wiring which can be produced to the building control inspector and only then can a DIY person who has done the work get the building control inspector to sign the work off for him.
What a rigmarole...
A registered spark who is also part p registered can ONLY sign off his own work(Building Control Part P). So working through this red tape is a nightmare regardless of how good the workmanship is.

So small to large firms use the similar process as a DIYer would need to follow but they get contractual discounts with Building Control depending on how many call outs are needed to inspect installs etc.

Self signing off your own work is only there to enable the local self employed tradesmen too sign off his own work. The only body allowed to sign off someone else work is Building Control. So all a registered spark can do when dealing with another persons work is test it and produce a test certificate, report in that certificate any codes if any etc, yes it is an easy 100 quid for a registered spark but such is the trade today and better safe than sorry.

Never confuse the Building Control Part P with a Registered electrical company or spark, yes it is confusing for the average Jo but hey that is the politics in the trade.

 

I totally agree with you fire, the trade is at an all time low in the domestic sector, just flooded with cowboys driving down prices. Part P is a sham. Unfortunately to make any money in domestic you have to be registered so it is a necessary evil, in order to be registered you have to jump through hoops. I was a big earner when I worked as an industrial spark for other companies, now I have been self employed for a number of years my earnings are mainly from domestic work which is in comparison to what I used to earn just scratching a living.

 

Aye Nigel one isolator to knock the whole lot off. I never use the DP Henley Blocks only the SP side by side (service connector blocks)..

 

Exactly, allot of customers don't realize this when they try to push us down on price. They want something for nothing for the most part.

As a self employed individual every time i tried too look at bank loans or mortgages i was seen as high risk so my interest rates which i was offered were over double that of someone who had a PAYE check every week. Friend of mine got a 4% rate while they offered me 15% just because i was self employed.
It is as if the system penalizes you for being self-employed but such is life, It is a tough industry.

 

So do I !!!.lol

 

For the difference in price between a split load board and one with rcbos go with the rcbos for the sake of £20

FYI A split load board should be installed with opposite circuits on the same rcd, ie upstairs lights & downstairs sockets one, downstairs lights, upstairs socket on two.

A ring circuit can do a circuit up to 100m² of floor area, a radial up to 50m²

Hope this helps!

 

Hi Guys, just to throw a spanner in the works. I just finished a new extension on my own bungalow. I retired from being an electrician around 8-9 years ago but wanted to do my own electrics, but i am not classed as qualified anymore. So i checked with the local council surveyor "who by coincidence used to be a sparks" if i could do my own electrics if it was signed of by another sparks. He told me a few years back this wasn't possible, but the regs have been relaxed & i can now do this.
Ditto with using Rcbo's so that if there is faults at some time in the future it is a lot easier to find, but i would be surprise if it was only £20 extra. A normal fuse is around 2-3 pounds each Rcbo's are around £13 each. Or am i out of touch?

 

Full loaded with rcbo's = Rolls Royce

Dual rcd = perfectly good

Both only as good as the person fitting them.

 

Depends on which make of board & RCBO you choose, some are from £16 each up to £36 each